1. Field of the Invention
The present invention relates to a display device and a method of fabricating a display device, and more particularly, to a backlight unit, a liquid crystal display device using a backlight unit, and a method of fabricating a liquid crystal display device.
2. Discussion of the Related Art
As the information age progresses, flat panel display (FPD) devices having light weight, thin profile, and low power consumption characteristics are being developed and commonly used as a substitute for cathode ray tube (CRT) devices. Generally, display devices may be classified according to their ability for self-emission, and may include emissive display devices and non-emissive display devices. The emissive display devices display images by taking advantage of their ability to self-emit light, and the non-emissive display devices require a light source since they do not emit light by themselves. For example, plasma display panel (PDP) devices, field emission display (FED) devices, and electroluminescent display (ELD) devices are commonly used as emissive display devices. Liquid crystal display (LCD) devices may be categorized as non-emissive display devices commonly used in notebook and desktop computers because of their high resolution, capability of displaying colored images, and high quality image display.
An LCD module of the LCD devices include an LCD panel for displaying images to an exterior and a backlight unit for supplying light to the LCD panel. The LCD panel includes two substrates facing and spaced apart from each other, and a liquid crystal material interposed therebetween. Liquid crystal molecules of the liquid crystal material have a dielectric constant and refractive index anisotropic characteristics due to their long, thin shape. In addition, two electric field generating electrodes are formed on the two substrates, respectively. Accordingly, an orientation alignment of the liquid crystal molecules can be controlled by supplying a voltage to the two electrodes, wherein transmittance of the LCD panel is changed according to polarization properties of the liquid crystal material. However, since the LCD panel is a non-emissive-type display device, an additional light source is required. Thus, a backlight unit is disposed under the LCD panel, wherein the LCD device displays images using light produced by the backlight unit. In general, backlight units may be classified into two types according to a disposition of the light source, such as side-type and direct-type. As display areas of the LCD devices become increasing larger, direct-type backlight units including a plurality of light source have become commonly used in order to provide high brightness.
FIG. 1 is an assembly view of a liquid crystal display module having a direct type backlight unit according to the related art. In FIG. 1, an LCD module includes an LCD panel 70, a direct-type backlight unit 5, and a plurality of combining elements thereof. The direct-type backlight unit 5 includes a bottom cover 10, a reflector 20, a plurality of cold cathode fluorescent lamps (CCFLs) 30, a pair of side supporters 40, an optical sheet 50, and a guide panel 60. The bottom cover 10 is commonly formed of metal or synthetic resin material and functions as a lower case. The reflector 20 is formed of metal material having one of a white and silver color, and is combined with the bottom cover 10. The plurality of CCFLs 30 are disposed parallel to each other over the reflector 20, wherein the pair of side supporters 40 cross two ends of each of the CCFL 30 to fix the plurality of CCFLs 30. The optical sheet 50 includes a plurality of diffusing sheets 50a, 50b, and 50c that cover the plurality of CCFLs 30 and the pair of side supporters 40. The guide panel 60 covers a rim portion of the optical sheet 50.
The plurality of CCFLs 30 are fixed by combining the pair of side supporters 40 and the bottom cover 10 using a plurality of first bolts 92. Thus, the direct-type backlight unit 5 is formed of a single body and includes the guide panel 60 and the bottom cover 10 combined together using a plurality of second bolts 94. In addition, an LCD panel 70 is disposed above the direct-type backlight unit 5, and a top cover 80 covering rim of the LCD panel 70 is combined with the bottom cover 10 using a plurality of third bolts 96 to complete the LCD module. Accordingly, light emitted from the plurality of CCFLs 30 is reflected by the reflector 20 and enters the optical sheet 50, and is uniformly supplied across an entire surface of the LCD panel 70 to display images having high brightness.
FIG. 2 is a cross sectional view along II—II of FIG. 1 showing the liquid crystal display module according to the related art. In FIG. 2, the guide panel 60 is combined with the bottom cover 10 using the plurality of second bolts 94, and the top cover 80 is combined with the bottom cover 10 using the plurality of third bolts 96. Although not shown, a pair of side supporters crossing two ends of each CCFL 30 is combined with the bottom cover 10 using the plurality of first bolts 92.
According to the related art, the entire LCD module must be disassembled and re-assembled to change or repair the direct-type backlight unit, i.e., the plurality of CCFLs 30. In general, the CCFLs 30 remain ON for an extended period of time and consume relatively large amounts of power. As a result, lifetimes of the CCFLs 30 are shortened and occasionally malfunction. Since the direct-type backlight unit includes the plurality of CCFLs 30, each of the CCFLs 30 may need to be changed or repaired more frequently. Thus, to change or repair any of the CCFLs 30, the entire LCD module must be disassembled and then re-assembled. In FIGS. 1 and 2, the top cover 80 and the LCD panel 70 are disassembled from the direct-type backlight unit 5 by unscrewing the plurality of third bolts 96. Then, the guide panel 60 is disassembled from the optical sheet 50 by unscrewing the plurality of second bolts 94, and then the side supporters 40 are disassembled from the bottom cover 10 by unscrewing the plurality of first bolts 92. Since the disassembled elements must be re-assembled after changing or repairing any of the CCFLs 30, a process of changing or repairing the CCFLs 30 is complicated and time consuming. Furthermore, since the LCD panel 70 is exposed during the process of changing or repairing the CCFLs 30, the LCD panel 70 may become contaminated and degrade image display quality. Accordingly, the direct-type backlight unit 5 must be changed even when a change or repair of one of the CCFLs 30 is necessary. Thus, production costs increase and efficiency of materials decreases.